1. Field of the Invention:
This invention relates to a needle attachment position indicator deice for use in sewing machines.
2. Prior Arts:
A sewing machine is known which permits selection of one of a plurality of sewing or stitch patterns, such as twin-needle/four-thread overlock stitching, double chain stitching, etc. due to its construction in which a looper may be connected to or disconnected from an oscillating shaft or motion of the machine may be changed, by means of a stitch shifting dial. Such a machine is so designed that the stitch patterns capable of being performed by the machine will be indicated on a front cover thereof by means of literal indications. Thus, rotation of the stitch shifting dial causes a lamp or lamps adjacent to the literal indications to be turned on, whereby one may determine which stitch pattern is selected.
It is sometimes necessary to change the needle position upon changing stitch pattern. Thus, conventional sewing machines include a needle clamp A having a plurality of needle attachment positions a1-a4, so that needles B may be selectively positioned (FIGS. 8 and 9). If the needles are erroneously positioned, the intended stitch pattern will not be formed. In particular, and when the needle clamp has four (4) needle attachment positions, it is difficult to determine which position needles are to be attached to. By this, attachment or detachment of needles requires a significant period of time, thus decreasing operation efficiency.